Electromagnetic flowmeter

An electromagnetic flowmeter comprising:

• magnetic field generation means for generating a magnetic field in a measuring tube, said magnetic field being perpendicular to an axial direction of said measuring tube and to be perpendicular to a gravitation direction such that an electromotive force generated in a fluid flowing in said measuring tube is not influenced by a fluid level of said fluid;
• flow rate output means for calculating a flow rate of said fluid flowing in said measuring tube based on a potential developed in said fluid by said magnetic field generated by said magnetic field generation means so as to output said calculated flow rate;
• and
• display means for displaying said flow rate calculated by said flow rate output means, wherein said magnetic field generation means comprises:
• a pair of excitation coils provided on an outer periphery of said measuring tube;
• and
• supply means for supplying an excitation current to each of said excitation coils to generate the magnetic field;
• wherein said excitation coils are arranged such that a line connecting to a center of each of said excitation coils is placed on an upper side in the gravitation direction with respect to a line which passes through the center of the measuring tube parallel to the axial direction of the measuring tube and perpendicular to the gravitation direction.

An electromagnetic flowmeter comprising:

• magnetic field generation means for generating a magnetic field that is both perpendicular to an axial direction of said measuring tube and perpendicular to a gravitation direction in a measuring tube;
• and
• flow rate output means for calculating a flow rate of fluid flowing in said measuring tube based on a potential developed in said fluid by the magnetic field generated by said magnetic field generation means and said level of fluid flowing in said measuring tube so as to output said calculated flow rate;
• and
• display means for displaying said flow rate calculated by said flow rate output means.

An electromagnetic flowmeter comprising:

• an earth ring, provided at an end portion of a measuring tube, for indicating an earth potential;
• magnetic field generation means for generating a magnetic field in said measuring tube to be perpendicular to an axial direction of said measuring tube and to be perpendicular to a gravitation direction;
• and
• flow rate output means for calculating a flow rate of fluid flowing in said measuring tube based on a potential, which is developed at a lower portion of said measuring tube and which is detected at a portion of said measuring tube separated from said earth ring by a distance more than an inner diameter of said measuring tube, said potential developed by said magnetic field generated by the magnetic field generation means and the earth potential indicated by said earth ring;
• and
• display means for displaying said flow rate calculated by said flow rate output means.

An electromagnetic flowmeter comprising:

• a pair of excitation coils, provided on an outer periphery of a measuring tube, for generating a magnetic field in said measuring tube, said magnetic fluid being perpendicular to an axial direction of said measuring tube and perpendicular to a gravitational direction, such that an electromotive force generated in a fluid in said measuring tube is not influenced by a fluid level of said fluid;
• a point electrode, provided at a lower portion in said measuring tube, for detecting a potential developed in said fluid by said magnetic field generated by said pair of excitation coils;
• a processor for calculating a flow rate of fluid flowing in said measuring tube based on the potential detected by said point electrode;
• and
• a display device for displaying said flow rate calculated by said processor .